1. Field of the Invention
The present invention relates to an emergency boom for use on a tanker for retaining material that leaks from the tanker.
2. Related Art
Recent tragedies involving oil spills suggest that existing techniques of avoiding or abating such disasters are insufficient. Even requiring that tankers be constructed or retrofitted with double hulls cannot be certain to avoid many disasters. Indeed, because a double hull decreases available cargo capacity by a substantial amount, it would seem likely that tankers with double hulls will have to become much bigger in order to compete with single hulled vessels. Consequently, disasters involving the double-hulled vessels can often be expected to be as bad as those involving single hulled vessels.
A number of prior art devices and methods have attempted to address the problem of how to respond once a leak in a tanker or a spill at an offshore oil rig has occurred. Most methods of response occur significantly after the fact of the spill, primarily because cleanup response devices and techniques cannot be transported to the source of the spill quickly enough. The desirability of an effective way to confine such spills at or near their source until response by distant parties can be effected has become clear to many.
A few examples of spill confinement techniques and devices already exist. U.S. Pat. No. 3,599,434 to Missud teaches the use of a floatable tube and skirt assembly to encircle an offshore oil drilling rig. The floatable tube and skirt assembly includes means for raising and lowering the skirt and retracting or extending the tube and skirt assembly. and retracting or extending the tube and skirt assembly. However, because the assembly can be left in the water on a drilling rig, obviously not a possibility on a vessel intended for transportation, there is not disclosed an acceptable means of withdrawing the assembly from the water for repackaging after use. The withdrawal means suggested in the reference would be too bulky for practical use on board a vessel.
U.S. Pat. No. 4,249,834 to Bouvier teaches the use of a flotation collar structure surrounding the periphery of a vessel in order to contain oil spills. One embodiment of the disclosure contemplates a deployable containment device surrounding the periphery of the vessel. However, while providing that such a device is capable of being stored, Bouvier proposes no technique by which a deployed device can be put back into storage.
U.S. Pat. No. 4,960,347 to Strange also contemplates the use of a barrier curtain deployed to contain a spill. In this disclosure the curtain may consist of several segments which are unfurled immediately around the leak or which may completely surround the vessel. A life boat davit may be modified to suspend the curtain over the vessel's edge and to permit furling and unfurling. This apparatus, however, is unwieldy and the document does not indicate that it might be possible to shield the apparatus from the elements while still being able to effectively deploy the curtain in emergencies.
Prior to the present invention, there was a need for a quickly deployable, effective and easily repackaged containment device aboard a tanker. In addition to the foregoing, there was a need for such a device that included means to permit periodic inspections of and repairs to the components of the device without engaging in a massive undertaking.